H.E.L. and M.J.H. contributed equally to this work.
Young children have an unacceptably high prevalence of diabetic ketoacidosis (DKA) at the clinical diagnosis of type 1 diabetes. The aim of this study was to determine whether knowledge of genetic risk and close follow-up for development of islet autoantibodies through participation in The Environmental Determinants of Diabetes in the Young (TEDDY) study results in lower prevalence of DKA at diabetes onset in children aged <2 and <5 years compared with population-based incidence studies and registries.
Symptoms and laboratory data collected on TEDDY participants diagnosed with type 1 diabetes between 2004 and 2010 were compared with data collected during the similar periods from studies and registries in all TEDDY-participating countries (U.S., SEARCH for Diabetes in Youth Study; Sweden, Swediabkids; Finland, Finnish Pediatric Diabetes Register; and Germany, Diabetes Patienten Verlaufsdokumenation [DPV] Register).
A total of 40 children younger than age 2 years and 79 children younger than age 5 years were diagnosed with type 1 diabetes in TEDDY as of December 2010. In children <2 years of age at onset, DKA prevalence in TEDDY participants was significantly lower than in all comparative registries (German DPV Register,
Participation in the TEDDY study is associated with reduced risk of DKA at diagnosis of type 1 diabetes in young children.
Recent epidemiological studies indicate that the incidence of type 1 diabetes is increasing worldwide, with the greatest increase in children aged <5 years (
Literature review of DKA at diagnosis in children under age 5 years
| Study country (reference) | Definition of DKA | Time of diabetes onset | DKA frequency % ( | ||
|---|---|---|---|---|---|
| <2 years of age | <3 years of age | <5 years of age | |||
| SEARCH, U.S. ( | 4 | 2002–2004 | NA | NA | 37.3 (458) |
| Austria ( | 1 | 1989–2008 | 60 (185) | NA | 43.7 (775) |
| Germany ( | 3 | 1987–1997 | NA | NA | 36.0 (470) |
| Germany and Austria ( | 1 | 1995–2007 | NA | NA | 26.5 (NA) |
| Canada ( | 5 | 1994–2000 | NA | 39.7% (390) | NA |
| Finland ( | 2 | 1992–2001 | 44.71, 54.22 (48) | NA | 23.71, 29.32 (137) |
| U.S. ( | 1 | 1995–1998 | NA | NA | 54.5 (44) |
NA, data not available. DKA defined as follows: 1 = pH <7.3; 2 = pH <7.3 and/or bicarbonate <15 mmol/L; 3 = pH <7.3 or bicarbonate <15 mmol/L and ketonuria; 4 = arterial or capillary pH <7.3/venous pH <7.25 or ICD 9 code 250.1 at discharge or DKA diagnosis mentioned in the medical charts; 5 = ICD 9 codes 250.1/250.2/250.3 from medical charts. Superscript numbers refer to DKA frequency calculated by DKA definitions 1 and 2.
Prevention of DKA would eliminate the potential morbidity and mortality associated with cerebral edema at diagnosis and may provide considerable cost savings by reducing days of hospitalization and use of intensive care units. Previous studies of autoantibody-positive children have demonstrated fewer episodes of DKA, reduced morbidity, and improved clinical care in children diagnosed through prospective screening and follow-up (
Several ongoing studies are following children at high genetic risk of type 1 diabetes from birth (
As such, the specific aim of this study was to determine if participation in a longitudinal study of the natural history of type 1 diabetes, The Environmental Determinants of Diabetes in the Young (TEDDY), in which the parents of young children (aged <5 years) are aware of their child’s increased risk for developing the disease, resulted in lower rates of DKA at diagnosis of type 1 diabetes compared with recent and ongoing population-based incidence registry studies conducted in countries also participating in TEDDY. Specifically, we hypothesized that DKA prevalence in young children participating in TEDDY (<2 years and <5 years of age at diagnosis) would be lower than the DKA rates of children participating in an observational study, SEARCH for Diabetes in Youth in the U.S. (
We compared symptoms and laboratory results collected for children participating in the TEDDY study (
At diagnosis of type 1 diabetes, data are collected from the treating physician using a standardized case report form requiring documentation that American Diabetes Association criteria for the diagnosis have been met (
For comparative analyses of DKA at onset, we obtained data from national incidence studies being performed in the same countries as the TEDDY study (for the European registers during 2004–2009 and for the U.S. study during 2004–2005). Data were limited to children <5 years of age at diagnosis.
SEARCH is a U.S. multicenter study aimed at identifying prevalent and incident cases of diabetes among individuals <20 years of age at diagnosis. For these analyses, we included children diagnosed with type 1 diabetes in 2004 and 2005. DKA was defined in the SEARCH protocol using medical abstraction to identify bicarbonate <15 mmol/L or venous pH <7.25 (arterial/capillary pH <7.30), International Classification of Diseases, Ninth Revision, code 250.1, or physician’s diagnosis of DKA. Our analysis included 275 SEARCH subjects diagnosed with type 1 diabetes when <5 years of age.
Swediabkids is the Swedish pediatric national quality registry for type 1 diabetes, covering 100% of all children diagnosed in Sweden. The incidence register is part of this national online follow-up quality register for pediatric patients, where all pediatric diabetes clinic visits are recorded. In this report, we include data from 651 Swedish children diagnosed with type 1 diabetes between 2005 and 2009 and <5 years of age at diagnosis. Of those, 44 children were excluded from this analysis due to missing pH or bicarbonate values. DKA was defined as arterial pH <7.30 and severe if arterial pH was <7.10.
The Finnish Pediatric Diabetes Register was established in 2002 and collects data on all children in Finland diagnosed with type 1 diabetes. Diabetes was diagnosed according to World Health Organization criteria, and DKA was diagnosed as arterial pH <7.30 and considered severe if arterial pH was <7.10. In children without arterial pH or bicarbonate data, negative urine ketones, negative blood ketones, or lack of symptoms (polyuria, polydipsia, and polyphagia) were used to exclude DKA. Our analysis includes 737 children aged <5 years from the Finnish Diabetes Register diagnosed with type 1 diabetes from 2005 to 2009.
The German/Austrian diabetes documentation and quality management system (DPV) is a continuous diabetes data acquisition system providing data from 53,485 type 1 diabetes patients throughout Germany and Austria. DKA is defined in the DPV as arterial pH <7.30 and severe DKA as arterial pH <7.10. In patients without biochemical data, chart abstraction and physician attestation of the patient’s condition at diagnosis is considered sufficient to rule out DKA. Our analysis includes 1,812 DPV children from the DPV diagnosed with diabetes from 2005 to 2009.
Because of differences in data collection and management of newly diagnosed patients within TEDDY, SEARCH, and the population-based registries, we used two definitions of DKA to ensure appropriate comparisons (
Definitions of DKA
| Study/register | Definition of DKA |
|---|---|
| TEDDY | Strict definition: DKA, arterial pH <7.30 or bicarbonate <15 mmol/L; severe DKA, arterial pH <7.10 or bicarbonate <5 mmol/L. Broad definition: DKA, arterial pH <7.30 or bicarbonate <15 mmol/L. If pH and bicarbonate values missing, DKA was diagnosed if urine ketones >40 mg/dL, blood ketones >3.0 mmol/L, or by physician’s diagnosis. |
| Swediabkids | DKA, arterial pH <7.30 (primary) or bicarbonate <15 (secondary); severe DKA, arterial pH <7.10 or bicarbonate <5 mmol/L. |
| SEARCH | DKA, bicarbonate <15 mmol/L, venous pH <7.25 or arterial pH <7.30 or International Classification of Diseases, Ninth Revision, code 250.1, or physician’s diagnosis of DKA. |
| Finnish Pediatric Diabetes Registry | DKA, arterial pH <7.30; severe DKA, arterial pH <7.10. In children without pH or bicarbonate data, negative urine ketones, negative blood ketones, or lack of symptoms (polyuria, polydipsia, polyphagia) were used to exclude DKA. |
| German DPV Registry | DKA, arterial pH <7.30; severe DKA, arterial pH <7.10. In patients without biochemical data, chart abstraction and physician attestation of the patient’s condition at diagnosis was used to exclude DKA. |
Data were analyzed using the Statistical Analysis System Software (Version 9.2; SAS Institute, Cary, NC). Prevalence estimates and 95% confidence intervals were calculated as the proportion presenting with DKA at the time of diagnosis by age-group (<2 and <5 years) based on appropriate definition (strict or broad). Rates were compared using χ2 statistics or Fisher exact test (for small samples, less than or equal to five per cell) to assess overall differences in prevalence estimates by study.
TEDDY screened 424,788 children for type 1 diabetes HLA risk, identified 21,588 eligible subjects, and enrolled 8,677 children. As of 31 December 2010, 80 TEDDY subjects were diagnosed with type 1 diabetes (
In children <2 years of age at diagnosis, 6 of 40 (15%) had DKA under the broad definition of DKA whereas 5 of 31 (16.1%) had DKA under the strict definition of DKA. TEDDY children diagnosed with type 1 diabetes before 2 years of age had lower rates of mild and total DKA when compared with population-based studies and registries (SEARCH,
DKA rates in children aged <5 years and <2 years at diagnosis
| Study | Total DKA | Mild DKA | Severe DKA | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| <2 years | <5 years | <2 years | <5 years | <2 years | <5 years | |||||||
| TEDDY (strict DKA definition) | 5/31 | — | 8/61 | — | 2/31 | — | 5/61 | — | 3/31 | — | 3/61 | — |
| 16.1% | 13.1% | 6.5% | 8.2% | 9.7% | 4.9% | |||||||
| (6.1–34.5) | (6.2–24.8) | (1.1–22.8) | (3.1–18.8) | (2.5–26.9) | (1.3–14.6) | |||||||
| TEDDY (broad DKA definition)Ŧ | 6/40 | — | 9/79 | — | 3/40 | — | 6/79 | — | 3/40 | — | 3/79 | — |
| 15% | 11.3% | 7.5% | 7.6% | 7.5% | 3.8% | |||||||
| (6.3–30.5) | (5.7–21.0) | (2.0–21.5) | (3.1–16.4) | (2.0–21.5) | (0.9–11.5) | |||||||
| Sweden registry | 51/129 | 0.02 | 102/604 | 0.45 | 39/129 | 0.005 | 78/604 | 0.41 | 12/129 | 1 | 24/604 | 0.73 |
| 39.5% | 16.9% | 30.2% | 12.9% | 9.3% | 4.0% | |||||||
| (31.2–48.6) | (14.0–20.2) | (22.6–39.0) | (10.4–15.9) | (5.1–16.0) | (2.6–5.9) | |||||||
| SEARCHŦ | 29/58 | <0.0001 | 100/275 | <0.0001 | NA | NA | NA | NA | NA | NA | NA | NA |
| 50.0% | 36.4% | |||||||||||
| (36.7–63.3) | (30.7–42.4) | |||||||||||
| Finland registryŦ | 82/183 | <0.0001 | 138/737 | 0.11 | 64/183 | 0.0005 | 114/737 | 0.06 | 18/183 | 0.77 | 24/737 | 0.74 |
| 44.8% | 18.7% | 35.0% | 15.5% | 9.8% | 3.3% | |||||||
| (37.5–52.3) | (16.0–21.8) | (28.1–42.4) | (12.9–18.1) | (5.9–15.1) | (2.1–4.8) | |||||||
| German registryŦ | 235/435 | <0.0001 | 583/1,812 | <0.0001 | 171/435 | <0.0001 | 458/1,812 | <0.0001 | 64/435 | 0.34 | 125/1,812 | 0.36 |
| 54% | 32.2% | 39.3% | 25.3% | 14.7% | 6.9% | |||||||
| (49.2–58.8) | (30.0–34.4) | (34.7–44.1) | (23.3–27.4) | (11.6–18.5) | (5.8–8.2) | |||||||
NA, data not available.
**
*All comparisons made to TEDDY strict definition.
ŦAll comparisons made to TEDDY broad definition.
In children <5 years of age at diagnosis, 9 of 79 (11.3%) had DKA at diagnosis of diabetes under the broad definition of DKA. Using the strict definition of DKA and excluding those with insufficient data, 8 of 61 (13.1%) <5 years of age had DKA at diagnosis of diabetes.
Total DKA (mild and severe DKA) at diagnosis was significantly less common in TEDDY participants (11.3%) when compared with SEARCH (36.4%) (
Although numbers were small, the rate of severe DKA (arterial pH <7.10) did not differ significantly between children diagnosed within the TEDDY study and those reported from national registries in any age-group. Notably, all three TEDDY children diagnosed with severe DKA were <2 years of age (8, 10, and 14 months, respectively) and had developed islet autoantibodies before clinical presentation of disease.
In this study we compared the prevalence of DKA in children participating in TEDDY and diagnosed with type 1 diabetes before the age of 5 years with national population-based registers. Our analyses demonstrate that TEDDY subjects diagnosed with type 1 diabetes before the age of 2 years experienced significantly less DKA at diagnosis (15%) when compared with new-onset patients reported in national diabetes registers from countries participating in TEDDY and the SEARCH study (35–50%). Similarly, TEDDY children diagnosed with type 1 diabetes before the age of 5 years experienced less DKA at onset when compared with children in the SEARCH study and the German DPV Registry, but not compared with children from the Finnish or Swedish registries. Although the relatively high proportion of TEDDY subjects who were first-degree relatives of type 1 diabetes patients may have confounded our analysis, DKA rates within the TEDDY cohort were similar among children recruited from the general population and those with a first-degree relative with type 1 diabetes, indicating that knowledge of diabetes risk and close longitudinal follow-up may be associated with reduced DKA risk regardless of family history.
Although our analysis is strengthened by the inclusion of data from a national incidence study and registries performed in each of the countries participating in TEDDY, we should note that children with incident diabetes from Colorado and Washington could have simultaneously been included in both the SEARCH and TEDDY databases, and the TEDDY participants in Sweden, Finland, and Germany could have been included in the national registries. While such an occurrence could have biased our data, the effect (given lower rates of DKA noted in TEDDY) would have been to mask the differences observed. As we were still able to document significant reductions in DKA when comparing TEDDY to SEARCH and the national registries, the effect of any potential bias was likely minimal. Unfortunately, we were unable to perform an analysis where participants in both TEDDY and a population-based study or registry were excluded.
Perhaps the most challenging issue related to inclusion of data from multiple national incidence registries was that of interpreting data with an appreciation of the different definitions of DKA used in each study (
When comparing overall DKA rates in TEDDY participants with children reported in the Swedish and Finnish registry, no significant differences were seen in children diagnosed before 5 years of age. However, rates of DKA in TEDDY participants aged <5 years were significantly lower when compared with children from the U.S. SEARCH study and the German registry. These observations are concordant with reports that countries with a high incidence of type 1 diabetes (Finland and Sweden) report reduced frequencies of DKA when compared with countries with lower incidence of type 1 diabetes. Decreased frequencies of DKA at onset of disease have been reported from Finland between 1982 and 2001, with a decrease from 22.4 to 15.2% in children 0–15 years of age and a decrease from 32.1 to 17.7% in children with onset before the age of 5 years (
The youngest children with new onset type 1 diabetes (<2 years of age) remain at high risk of DKA (
Unfortunately, our analysis lacked the power to determine if participation in TEDDY reduced the risk of severe DKA in children <2 years of age. That said, the observation of reduction in overall DKA in the youngest patients with new-onset diabetes suggests that participation in a longitudinal natural history study with provision of updated autoantibody risk information, frequent follow-up, and scheduled laboratory evaluations (autoantibodies, HbA1c, glucose, and OGTT) to diagnose asymptomatic cases is associated with reduced DKA risk. Although potentially cost prohibitive outside the constraints of a research protocol, combined approaches to educate communities on signs and symptoms of DKA (as in the Parma, Italy experiments) and to provide genetic or antibody screening to further identify high-risk subjects may eventually be required to achieve the goal of entirely preventing DKA in children.
DKA is a serious condition with high morbidity and risk of developing cerebral edema (for a review see Levin [
In conclusion, intensive longitudinal follow-up and continuous education regarding diabetes risk, as provided in diabetes prediction studies such as TEDDY, may yield direct benefit to young children diagnosed with type 1 diabetes through early diagnosis and reduction of DKA risk. Ongoing efforts to reduce and eliminate DKA at diagnosis in young children are urgently needed.
This article contains Supplementary Data online at
A complete list of the members of the TEDDY Study Group, SEARCH Study Group, Swediabkids Study Group, DPV Study Group, and Finnish Diabetes Registry Study Group can be found in the
TEDDY is funded by DK-63829, -63861, -63821, -63865, -63863, -63836, and -63790 and Contract HHSN267200700014C from the National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Allergy and Infectious Diseases, National Institute of Child Health and Human Development, National Institute of Environmental Health Sciences, Juvenile Diabetes Research Foundation, and Centers for Disease Control and Prevention. SEARCH for Diabetes in Youth is funded by the Centers for Disease Control and Prevention (PA numbers 00097, DP-05-069, and DP-10-001) and supported by the National Institute of Diabetes and Digestive and Kidney Diseases. Funding for DPV initiative was provided by Bundesministerium fuer Bildung und Forschung Competence Net Diabetes (FKZ 01GI0859). The site contract numbers are as follows: Kaiser Permanente Southern California, U48/CCU919219, U01 DP000246, and U18DP002714; University of Colorado Denver, U48/CCU819241-3, U01 DP000247, and U18DP000247-06A1; Kuakini Medical Center, U58CCU919256 and U01 DP000245; Children’s Hospital Medical Center (Cincinnati), U48/CCU519239, U01 DP000248, and 1U18DP002709; University of North Carolina at Chapel Hill, U48/CCU419249, U01 DP000254, and U18DP002708-01; University of Washington School of Medicine, U58/CCU019235-4, U01 DP000244, and U18DP002710-01; Wake Forest University School of Medicine, U48/CCU919219, U01 DP000250, and 200-2010-35171.
No potential conflicts of interest relevant to this article were reported.
H.E.L. wrote the manuscript. K.V. and R.B. researched data and reviewed and edited the manuscript. D.D. reviewed and edited the manuscript and contributed to discussion. L.D. and C.P. reviewed and edited the manuscript. M.K. researched data, reviewed and edited the manuscript, and contributed to discussion. R.V. reviewed and edited the manuscript. B.L. researched data and reviewed and edited the manuscript. U.S. reviewed and edited the manuscript. R.H. researched data and reviewed and edited the manuscript. M.J.H. wrote the manuscript.